دانلود کتاب Biological Control

The explosive increase in the world's human population, with conse­ quent need to feed an ever-increasing number of hungry mouths, and the largely resultant disturbances and pollution of the environment in which man must live and produce the things he needs, are forcing him to search for means of solving the first problem without intensifying the latter. Food production requires adequate assurance against the ravages of insects. In the last three decades short-sighted, unilateral and almost exclusive employment of synthesized chemicals for insect pest control has posed an enormous and as yet unfathomed contribution to the degradation of our environment, while our insect pest problems seem greater than ever. Properly viewed, pest control is basically a question of applied ecology, yet its practice has long been conducted with little regard to real necessity for control, and in some cases, with little regard to various detrimental side-effects or long-term advantage with respect, even, to the specific crop itself. This book deals fundamentally with these questions. The development of pesticide resistance in many of the target species, against which the pesticides are directed, has occasioned an ever-increasing load of applications and complexes of different kinds of highly toxic materials. This has been made even more "necessary" as the destruction of natural enemies has resulted, as a side effect, in the rise to pest status of many species that were formerly innocuous. The application of broad-spec­ trum pesticides thus has many serious and self-defeating features.